Condensation on new replacement windows, Why?

Single gal homeowner here wondering why my new replacement windows have condensation inside them. I live in the New England area and have noticed that my new replacement windows in some rooms have water inside them near the bottom of the window. The brand name escapes me right now. Here are some facts below about the windows and there location in the home:

- 1st they are single pane windows. (not sure if this has any relevance)
- the windows that have the most condensation are in the bedroom facing the north side of the house and this particular bedroom is situated on top of my garage. (note: this room is the coldest room in the house)
- other window is in the front on the house, north side, situated next to front door.
- note: windows facing the south and east end of the home getting the most sun are fine (no condensation).

Any thoughts would be appreciated......and thanks for reading my post.

- 1st they are single pane windows. (not sure if this has any relevance)!!!!! ( Italics mine). Most places it is not even legal to install single pane windows anymore!!!
- the windows that have the most condensation are in the bedroom facing the north side of the house and this particular bedroom is situated on top of my garage. (note: this room is the coldest room in the house)
- other window is in the front on the house, north side, situated next to front door.
- note: windows facing the south and east end of the home getting the most sun are fine (no condensation).

Any thoughts would be appreciated......and thanks for reading my post.

Click to expand...

Single pane windows get cold. Warm moist air from inside the house hits that and you get condensation. The type of heating system you have can be relevant, as is the number of hot steamy showers, amount of cooking, number of people, etc.

The cold single pane windows are the problem, but if too-high humidity is a problem , then a DE-humidifier may be called for. Many areas of the country need HUMIDIFIERS in the winter, so you would have to investigate.

Don't confuse a single assembly of multiple panes of glass as a single pane window. If you in fact really have single pane, it isn't unusual at all to get condensation without a storm window to help keep the inner surface warm.

If the condensation is INSIDE of the window (i.e., between the two external layers), the window has failed, find your purchase info, receipts, etc., as if they are new, most places have at least a few years, and 10 or more isn't uncommon for the insulating glass assembly. If it is truely on the room side, and not inside, even if it is an insulated glass assembly, it will be colder than the wall, and if the humidity is high enough and the dew point of the glass is such that you get condensation, it will happen. As Jimbo mentioned, most places need to add humidity in the winter and with modern insulated glass panels, condensation isn't all that common except in more extreme conditions (either really cold outside or high humidity inside).

The main question is WHY anyone would go to the expense of replacing windows and use single pane ones? They are always inefficient, both Summer and Winter, and condensation is just a symptom of their inefficiency.

Ok folks thanks for your replies.....being a single, female homeowner, I was very confused about purchasing replacement windows. I asked around about how to purchase them and I did spend a lot of money replacing the original windows but there is an overload of information on replacement windows. The single pane window is less expensive which is what I had to consider. Last night I checked the windows in question and I wiped a lot of moisture from the outside of the windows, but it does appear both on the outside and inside of the windows. Thanks Jimbo, Jar546 and HJ. Oh, by the way my heating system is gas, forced hot air if that matters. Man, now I wish I spent the extra money on the triple pane.....the single pane windows are very cold.

"Don't confuse a single assembly of multiple panes of glass as a single pane window. If you in fact really have single pane, it isn't unusual at all to get condensation without a storm window to help keep the inner surface warm. "

I am going to check my papers on the windows I purchased...I am confused and will get back to everyone.

easy way to tell multiple panes: hold a flame in front of the window (not directly on it, within a foot is fine) and move it back and forth. Count how many flames you see reflected in the window, thats how many panes you have.

Condensation on the exterior of the windows, oddly enough, is a good thing. It shows that the windows are "working" (I had this happen within days of getting really ncie expensive replacement windows........at first I freaked, then I read around and found out its a good thing).

Condensation on the INTERIOR is not a good thing. Several possible causes.......leaking air is one of them. Also, if you have window coverings, you might want to lift them off the sill an inch or two........without air to circulate behind them, the windows will condense. Finally, if you have a humidifier setup on your forced hot air, it might be set too high.

Thanks Chris for your advice......I checked the windows last night and wiped away a lot of moisture with a paper towel at the bottom of the windows and on the top as well. I am looking for the paperwork on the window purchase, but I do know that they are a very good brand.

I will make another check this weekend to see if any moisture appears on the interior of the windows.....I am hoping that there is none and its only on the outside as I stated above.

(1) Questions for anyone: Not having much knowledge about replacement windows, I was wondering why replacement windows do not come with a storm window. I would assume the newer glass quality replaces the need for a storm window.

(2) Also,I do notice that in a strong rain storm, the screens get pounded with rain....am I supposed to take the screen out?

Leave the screens in. Single pane windows in the winter time equals a cold piece of glass, and a cold piece of glass ALWAYS means condensation unless your house is unhealthily arid. If you have double hung windows, then storm windows may replace the screens, but if they are sliders it doesn't work because the screen is only behind one section, and the storm window will be a complete unit that mounts over the regular window.

Your old windows probably didn't have condensation because they leaked enough to dissipate the moisture. Now that you've replaced the windows air exchange has been limited so that moisture is trapped in the house and shows up as condensation on the single pane windows.

I suggest you look into storm windows or replace the single pane windows with thermally protected double or triple pane windows. Single pane windows are woefully inadequate in New England.